Wood cupping

Wood cupping describes where a plank or piece of wood bends across it with or across its grain and is the impact of shrinkage. When wood is observed in cross secrion wood cuts normally cup in the opposite direction to the flow of growth rings.

This characteristic may be used to its advantage for example where two layers of wood planks are used as roof sarking or vertically in fencing. In a roof the outermost planks are laid to cup downwards, whilst the layers beneath are laid to cup upwards, this causes the plank curves to tighten against each other over time, thus creating a better seal for the roof face.

[edit] Related articles on Designing Buildings

• Carpentry.
• Facts about forestry.
• Janka hardness rating scale.
• Nails - a brief history.
• Sustainable timber.
• Staircase.
• The differences between hardwood and softwood.
• The use of timber in construction.
• Timber.
• Timber vs wood.
• Types of timber.
• Types of timber species.
• Whole life carbon assessment of timber.
• Wood around the world.

Comments

[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.